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Abstract: Raman scattering and polarization-dependent synchrotron radiation X-ray absorption, in combination, have been employed to examine the residual stress of undoped GaN epitaxial layers grown on Si by molecular beam epitaxy and Si-doped n-type GaN layers grown on sapphire by metalorganic chemical vapor deposition. Values of the lattice constant of different GaN films can be deduced from the interatomic distances in the second coordination shell around Ga by polarization-dependent extended X-ray absorption fine structure analysis and the strain of the films can be obtained. This result is further confirmed by Raman scattering spectra in which the phonon modes show a significant shift between different GaN epitaxial layers with different growth conditions. [Copyright &y& Elsevier]

Abstract: Two sets of (Al x Ga1−x )0.5In0.5P films were grown on lattice-matched GaAs by low pressure metalorganic chemical vapor deposition under different conditions and studied by Nomarski microscopy (NM), atomic force microscopy (AFM), photoluminescence (PL) and Raman scattering. NM and AFM images show cross-hatch patterns, related to dislocations and lattice mismatch, from one set of samples, but none from another set of films. Comparative PL and Raman measurements and analyses indicated the correlation between surface and optical properties. The degree of variations in compositions and film quality with the growth conditions was found from the spectral analyses. Raman spectral features are more sensitive to the sample growth parameter variations. The line shape analysis of line width, integrated intensity ratio and spatial correlation model fitting leads to information about the order of the sample crystalline quality. The optimum growth conditions have been obtained from our comprehensive analyses. [Copyright &y& Elsevier]

Highly textured lead lanthanum titanate (Pb1-xLax)TiO3 (PLT) thin films have been grown on fused quartz substrates by metalorganic chemical deposition (MOCVD). A series of PLT with different x between 0 and 0.32 were prepared and studied by Raman scattering. Raman spectra, measured at 300 K and 80 K, showed the features from the PLT film and quartz substrate. By using a “difference Raman” technique, more PLT modes are shown. The variations of the PLT Raman modes with the La composition and the measurement temperature are studied, and related physical phenomena and problems are discussed. [Copyright &y& Elsevier]

Studies the effects of carbon-aluminum ion coimplanted epitaxial silicon carbide by Raman scattering measured at room temperature. Amorphization and damage to ion implantation; Evidences of the crystallization.

Examines the Raman scattering and x-ray diffraction of lead lanthanum titanate thin films. Use of metalorganic chemical vapor deposition to prepare the thin films; Alignment of crystallographic axes of the films; Decrease in the tetragonality of the crystal structure.

Examines the Raman spectra of lead titanate thin films grown by metalorganic chemical vapor deposition. Use of single-crystal KTaO[sub 3] and fused quartz as substrates; Overview of soft-mode theory; Shift in optical mode frequencies for the thin films and substrates.

Abstract: Wurtzite-structure MgxZn1−xO materials with five different compositions of x from 0 to 0.14 were grown on sapphire substrates by metalorganic chemical vapor deposition. It was found that increasing Mg content in the MgxZn1−xO not only increased the band gap energy of the film but was also beneficial to the epitaxial growth of p-type MgxZn1−xO without using any doping sources. In addition, the combined ultraviolet photoluminescence (PL) and Raman scattering spectra were measured with PL–Raman signals obtained together, showing a blue-shift of PL band and variation of resonant Raman multi-order longitudinal optical phonon modes with an increase of Mg content. [ABSTRACT FROM AUTHOR]